The league, based on assessment of each regime from a panel of experts, was topped for the second year in a row by the DASH Diet, which delivered the best results in terms of nutritional value, safety, weight-loss, and in preventing diabetes and heart disease.

An acronym for Dietary Approaches to Stop Hypertension, it advocates fresh produce, whole grains, lean protein and is low in fat and salt.

The site's verdict read: 'Though obscure, it beat out a field full of better-known diets.